This project has the following objectives for the coming year: 1) New methods will be developed for the control of plasma pH and pCO2 during platelet aggregation studies. 2) These methods will be applied to patient studies in order to demonstrate that the effects of pH in platelet aggregation demonstrated in vitro also apply in vivo. 3) Dog studies will be performed to document the effect of hyperventilation on platelet aggregation in vivo utilizing new techniques to discern platelet aggregates in flowing blood (screen filtration pressure). 4) The role of complement in endotoxin-induced pulmonary edema will be assessed in mice using decomplementation with cobra factor. 5) The details of C3PA conversion by magnesium ion will be investigated. 6) The machanism of platelet interaction with non-phagocytosable immune complexes will be investigated.